Experimental assessment of dry precast beam column connections under progressive collapse scenario

Abstract

Progressive collapse denotes a failure of a major portion of a structure that has been initiated by failure of a relatively small part of the structure such as failure of any vertical load carrying elements (typically columns). Failure of large part of any structure will results into substantial loss of human lives and natural resources. Therefore, it is important to prevent progressive collapse which is also known as disproportionate collapse. Recently, there is increasing trend towards construction of buildings using precast concrete. In precast concrete construction, all the components of structures are produced in controlled environment and transported to the site. At site, such individual components are connected appropriately. Connections are the most critical elements of any precast structure, because in past, major collapse of precast structure took place because of connection failure. In this study, behavior of three different 1/3ʳᵈ scaled dry precast concrete beam column connections under progressive collapse scenario is assessed and their performance is compared with monolithic connection. Precast connections are constructed by adopting different connection detailing at the junction by considering reinforced concrete corbel for two specimens and steel billet for one specimen. In precast connection, beam is connected with column by means of cleat angles stiffened by using single stiffener and double stiffener. Performance of specimen is evaluated on the basis of ultimate load carrying capacity, maximum deflection and deflection measured along the span of the beam. From the results, better performance of precast connections is observed up to elastic phase but later on its strength degrades more as compared to monolithic connection. So, ultimate load carrying capacity of precast connections is lower than that of monolithic connections, which necessitates improved detailing of precast connections to enhance their performance during progressive collapse scenario.